Round control device



Nov. 12, 1968 B. l. PISKATOR ROUND CONTROL DEVICE 2 Sheets-Sheet 1 FiledNov. 13, 1967 Nov. 12, 1968 l. PISKATOR ROUND CONTROL DEVI CE Filed Nov.13, 1967 NVENTOR El E Ilq- I Piskuur BY` #LM/; M, X

ATTORNEY United States Patent O 3,410,173 ROUND CONTROL DEVICE Bengt I.Piskator, Chicopee Falls, Mass., assigner to the United States ofAmerica as represented by the Secretary of the Army Filed Nov. 13, 1967,Ser. No. 682,685 Claims. (Cl. 8933) ABSTRACT 0F THE DISCLOSURE A frontand a rear pair of round control units are located in the receiver of aknown automatic firearm so that the units in each pair are disposed 90apart on opposite sides of a cartridge feed port and opposite a pair ofround stops so as to cooperate therewith in holding a cartridge at afeeding position after passing through the feed port. Each of the roundcontrol units includes a compression-torsion spring with an extendingarm and the round control units in each pair are arranged so that thearms are pressed apart by the cartridge when transferred to the feedingposition and then spring back to cooperate with the round stops. Thearms are swung rearwardly by the reciprocating barrel to preventinterference therewith when moving rearwardly to envelop the feedposition cartridge.

The invention described herein may be manufactured, used, and licensedby or for the Government for governmental purposes without the paymentto me of any royalty thereon.

The invention relates to machine guns of the type disclosed in U.S,Patents 3,318,191 to Reed, 3,320,855 to Reed etal, and 3,340,770 toSantos. Trouble has ben experienced with such machine guns because ofjamming caused by the cartridge in the feeding position being misalignedwith the barrel chamber as the barrel moves rearwardly to envelop it fordischarge. This misalignment results from the cartridge being held bythe feed pawl and apair of round stops solely at the area of the centerof gravity. This support is not sufcient to completely secure thecartiridge against teetering caused by weapon vibration during tiringand therefore when the teetering is severe the front end of thecartirdge contacts the rear face of the rearwardly moving barrel ratherthan enter the chamber, causing the machine gun to jam.

It is, therefore the principal object of this invention to providesimple but effective means for securely holding the feeding positioncartridge against teetering. Such means include four round control unitsarranged as a front and a rear pair simultanneously contactable by acartridge, when moved to the feeding position, forwardly and rearwardlyof its center of gravity. Each of the round control units include acompression-torsion spring with a tangentially extending arm portion. Ineach pair the arms extend angularly into the path of movement of thecartridge when moved to the feeding position so as to be pressed apartby the cartridge during movement thereto. The arms spring back to theirnormal positions for terminal contact with the cartridge when it reachesthe feeding position.

A further advantage of this invention is that it eliminates any need tochange the components of the machine gun when cartridges having cases ofdifferent material are used. A change in case material changes thecenter of gravity of the cartirdge, sometimes considerably, and wherethe feeding position cartridge is supported in the area of the center ofgravity this requires that the feed pawl and round stop components bechanged to conform to the new location thereof.

The specific nature of the invention as well as other objects andadvantages thereof will clearly appear from 3,410,173 Patented Nov. l2,1968 a description of a preferred embodiment as shown in theaccompanying drawings in which:

FIG. 1 is an elevational view of the receiver and cam drum section of amachine gun of the aforementioned type:

FIG. 2 is an enlarged view taken along line 2 2 of FIG. 1 and shows acartridge moved by the feed pawl towards the feeding position and thebarrel located in its forward position;

FIG. 3 is a view similar to FIG. 2 but shows the cartridge in thefeeding position;

FIG. 4 is a view similar to FIG. 3 but shows the barrel adjacent itsrearward firing position;

FIG. 5 is an enlarged exploded view of one of the control units;

FIG. 6 is a view taken along line 6 6 of FIG. 3;

FIG. 7 is a View taken along line 7-7 of FIG. 2.

Shown in the figures is a machine gun 12 having a receiver 14 and abarrel 16 which reciprocates between a forward cartridge loadingposition and a rearward tiring position. A feeding mechanism 18 includesa feed pawl 20 arranged for vertical reciprocating to transfer acartridge 22 downwardly to a feeding position in coaxial alignment withbarrel 16, Receiver 14 includes a feed port 24 through which cartridge22 is transferred into the receiver and an ejection port 26 located inthe bottom of the receiver for ejection of the fired case of thecartridge therethrough.

'Cartridge 22 is stopped in the feeding position by a pair of roundstops 40 which are fully described in U.S. Patent 3,340,770. Each of theround stops 40 is mounted in a longitudinal channel 42 provided thereforin receiver 14 and such channels are symmetrically disposed apart onopposite sides of ejection port 26. A tongue 43 on each of the roundstops 40 provides the point of contact between the round stop andcartridge 22 and the tongues are arranged to contact the cartridge atapproximately the center of gravity thereof, noted at C.G. in FIG. 6.Round stops 40 are each pivotally mounted between the front and rearends thereof on a pin 44 so as to be displaceable by barrel 16 between astopping position wherein tongues 43 are positioned to stop cartridge 22at the feeding position and an open position wherein the tongues areclear of the barrel when adjacent its tiring position, to preventinterference therewith, and of ejection port 26 to permit passage of thefired case of the cartridge therethrough.

When cartridge 22 is located in its feeding position it is held steadytherein ready for envelopment by barrel 16 by four round control units46 which are mounted in receiver 14 as a front pair and a rear pairwhich are simultaneously contactable by the cartridge during transfer tothe feeding position. The front pair contact cartridge 22 forwardly ofthe center of gravity thereof and the rear pair rearwardly of the centerof gravity as is especially shown in FIG. 6. In each pair, round controlunits 46 therein are located 90 apart on opposite sides of feed port 24so as to be symmetrical therewith and therefore are oppositely disposedrelative to round stops 40, as shown in FIGS. 2-4, to cooperatetherewith in holding cartridge 22 against teetering when in the feedingposition.

Each of the round control units 46 includes a mount 51 having a shaft 52with an essentially rectangular head 54 fixed to one end at right anglesto its longitudinal axis. The opposite end of shaft 52 is bifurcated bya slot 56. Coiled around shaft 52 is a spring 58 which functions as acompression spring in one plane and as a torsion spring in another andwhich includes a plurality of spaced coils 60. The end of spring 58 thatabuts inner face 62 of head 54 is terminated by an arm 64 which extendstangentially from the last one of the coils 60. The opposite end ofspring 58 is terminated by locking section 66 that extends diametricallyacross the last one of the coils 69 so as to be receivable by slot 56and thereby anchor that end of the spring to mount 51. Arm 64 issufficiently rigid to withstand any linear pressure which may be appliedby cartridge 22 to the end thereof, during operation of gun 12, withoutbending. The free end of arm 64 is terminated by a semicircular contactsection 68 which extends rearwardly from the arm to provide arcuatecontact of the arm with barrel 16 during reciprocation thereof.

Round control units 46 are mounted in receiver 14 within a pair oflongitudinal channels 70 disposed on opposite sides of feed port 24 soas to be spaced 90 apart and symmetrical therewith. Extending similarlyinto each of the sides of channels 70 that face towards feed port 24 aretwo longitudinally spaced bores 72 the axes of which are normal to theextension of a radius respective to the longitudinal axis of barrel 16.Shafts 52 of the front pair of round control units 46 are received bythe front ones of the bores 72 and the shafts of the rear pair arereceived by the rear ones of the bores. Bores 72 are each counter-boredat 74 to an annular ledge 76 for receiving spring 58.

Each of the round control units'46 is installed in receiver 14 byintroducing the free end of its shaft 52 into one of the bores 72 andthen pressing inwardly so that spring 58 thereon is partially compressedbetween ledge 76 and inner face 62 so as to be preloaded. Mount 51 isthen locked in position by a pin 78 inserted through an accommodatingaperture 80 in receiver 14 and cooperating holes 82 through shaft 52.

When round control units 46 are installed, arms 64 extend angularly intothe path of movement of cartridge 22 when moved by feed pawl 20 to thefeeding position with the arms of the front pair being directly oppositeeach other as are the arms of the rear pair. Thus, arms 64 are camminglypressed apart by cartridge 22 when moved by feed pawl to the feedingposition, the sidewise displacement of the rms causing an obliquecompression of coils 60 in springs S8 as shown in FIG. 2. Whencartrid-ge 22 reaches the feeding position, arms 64 are free to snapback to their normal positions in contact with the related inner faces62 under the influence of the compressed coils 60, as shown in FIG. 3,whereby the cartridge is supported at the center of gravity by roundstops and is held against teetering thereon by arms 64 of the front andrear pairs of the round control units. Arms 64 hold cartridge 22securely through the rigidity of the arms and the preload introducedinto springs S8 during installation which holds the arms resilientlyagainst inner 'faces 62.

When barrel 16 moves rearwardly to envelop cartridge 22, rear face 84 ofthe barrel camming contacts arms 64 of the front pair of round controlunits 46, when the projectile of the cartridge is located within thebarrel, and is thereby secured against jamming, this contact swings thearms 64 upwardly, winding the respective springs 58, into channels 70and out of interference with barrel 16. During continued rearward travelof barrel 16 arms 64 of the rear pair of round control units 46 arecammingly contacted by rear face 84 and are similarly cammed out ofinterference with the barrel.

When the chambered cartridge 22 is fired and barrel 16 moves forwardlyarms 64 are released after rear face 84 passes thereby and are swung totheir normal positions, under the influence of the torque introduced insprings 58 when wound, ready to aid in supporting the next incomingcartridge.

The present invention has been described in detail above for the purposeof illustration only and is not intended to be limited by thisdescription or otherwise except as defined by the scope of the appendedclaims.

I claim:

'1. In a machine -gun having a receiver, a barrel disposed forlongitudinal reciprocation between a forward cartridge loading positionand a rearward ring position and a feeding mechanism including avertically reciprocating feed pawl for transferring a cartridge througha feed port in the receiver downwardly to a feeding position therein incoaxial alignment Iwith the barrel for envelopment thereby, thecombination including a pair of round stops arranged to stop downwardtransfer of the cartridges by the feed pawl at the feeding position, a

plurality of pairs of round control units, one pair of said roundcontrol units being mounted in the receiver on opposite `sides of thefeed port and forwardly of the center of gravity of the cartridge whenin the feeding position, one pair of said round control units beingmounted in the receiver on opposite sides of the feed port andrearwardly of the center of gravity of the feeding position cartridge,each said round control units including a spring designed to function asa torsion spring in one plane and as a compression spring in another,and a mount for mounting said spring in the receiver so as to becompressed by the cartridge during transfer to the feeding position andthen snap back vto normal position to cooperate with the mound stops inholding the cartridge against teetering when in the feed position and soas to be wound by the barrel out of interference therewith duringenvelopment of the cartridge.

2. The invention as defined in claim 1 wherein said spring includes anarm arranged when in a normal position for terminal contact With thecartridge opposite said round stops to cooperate therewith in holdingthe cartridge against teetering in the feeding position and for angularextension into the path of movement of the cartridge to the feedingposition so as to be deflected out of interference therewith by cammingcontact of the cartridge.

3. The invention as defined in claim 2 wherein said spring is mounted bysaid mount in the receiver so that said arm is swung rearwardly to windsaid spring by Contact of the barrel with said arm during travel to therearward firing position, and including a channel in the receiver forreceiving said arm when swung rearwardly by the barrel.

4. The invention as defined in claim 3 wherein said spring includes aplurality of coils sufficiently spaced to permit oblique compressionthereof by said arm when deflected by the cartridge and said arm extendstan- `gentially `from one end of said spring, and a locking sectionformed at the opposite end of said spring so as to be received by a slotin said mount for anchoring the opposite end of said spring thereto.

5. The invention as defined in claim 4 wherein said mount includes ashaft bifurcated at one end by said slot and arranged to be insertedthrough said coils, a head .-xed to the opposite end of said shaft, andan inner face of said head resiliently contacted by said arm to holdsaid arm in its normal position against deflection by the cartridgeafter reaching its feeding position.

References Cited UNITED STATES PATENTS 3,311,021 3/1967 Reed 89-33BENJAMIN A. BORCHELT, Primary Examiner.

S. C. BENTLEY, Assistant Examiner.

